1. Field of the Invention
The present invention sets forth a vehicle structure and provides a method for improving a military vehicle of the armored, tracked, troop carrying type to create a more cost-efficient, producible design with improved vertical obstacle crossing capability, and higher off-road cross country mobility.
2. Description of the Prior Art
Armored tracked vehicles of the troop carrying type, such as an "M113" armored personnel carrier, have been in production for over 35 years. This type of vehicle has been used for various services, including as a command post, missile launcher, hazardous material incidents respond vehicle, cargo carrier, ambulance, reconnaissance and recovery vehicle. The same chassis structure has been used for each of these vehicle types. The traditional design of this family of vehicles included two box beam extrusions, forming lateral perimeter frame members of the hull. These box beam extrusions extend from the front of the vehicle to the back of the vehicle. Integrated to the outboard surfaces of each of the box beam extrusions are lower side plates, personnel protection plates and the five roadwheel trunnion mounting pads or "bogey" pads used to accommodate the suspension of the vehicle.
In the current production model of this vehicle, the joining of the lower side plates and the personnel protection plates to form the lower hull is labor intensive and time consuming. First, the personnel protection plate, sometimes referred to as a doubler, had to be welded to the lower side plate. The resultant subassembly then had to be subjected to a straightening procedure to restraighten the lower side plate weld processing distortion. Afterwards, the subassembly, consisting of the lower side plate and the doubler, had to be welded to the box beams. Again, the lower side plate assembly had to be straightened due to the weld process distortion from welding the lower side plates to the box beams. At this point of fabrication of the lower hull, the last remaining significant element to be completed was the welding of the bogey pads to the exterior vehicle surface of the box beams. In some instances, even at this stage, the final lower side plate would need straightening due to the weld process distortion from welding the bogey pads to the lower side plate assembly.
U.S. Pat. No. 5,490,314, Stretch Vehicle Conversion Method, included modification procedure that resulted in an upper hull that was mostly discarded and recycled because of where the original upper hull had to be cut to accommodate the replacement stretched lower hull. In the instant invention, the upper hull is largely reused in the improved modified hull presented here. As a result, the intact equipment mounting provisions, that is, the myriad attachment points, fixtures and surface indentations do not have to be refabricated on a totally new hull as they are intact on the original hull. This results in tremendous time savings in the conversion process.